Mass production of ophthalmic lenses generally comprises one or more wet treatment processes, in which the ophthalmic lenses are treated with a variety of solutions in a variety of ways to modify the properties of the ophthalmic lenses. For example, contact lenses are typically subjected to extraction processes during the manufacture of the lens in order to remove unpolymerized monomers or macromers from the molded lens, or to hydration processes during the manufacture of the lens in order to remove undesired solvents originating from the polymerization or molding steps. Contact lenses may also be subjected to tinting processes, in which the contact lenses are exposed to a treatment solution (tinting solution) containing a reactive dye in order to impart ultraviolet (UV) light absorbing properties or visible light absorbing properties to the lens. Another example of wet treatment of contact lenses involves exposure of the lens to a monomer solution with graft polymerization being induced to alter the surface properties of the lens. A further example is that contact lenses are subjected to layer-by layer processes (LbL) as disclosed in a pending U.S. patent application Ser. No. 09/199,609 filed on Nov. 25, 1998, now abandoned in order to increase hydrophilic properties of the lenses. LbL processes typically involve consecutively dipping of the lenses into solutions of oppositely charged polyionic materials until a coating of a desired thickness is formed.
In order to efficiently and economically treat lenses with solutions, one may treat many lenses at one time by placing each lens in a compartment within a tray having numerous cavities. Typically, the lenses are confined in wells which can prevent the lenses from inverting or rolling over. Such a tray holding numerous lenses may be immersed in a container holding an extracting solution, a hydrating solution, a rinsing solution, a tinting solution, a monomer grafting solution, or a LbL coating solution in order to efficiently treat many lenses at once. However, there are problems associated with switching from one wet treatment to another. For example, an extraction process may be carried out in a first container having an extracting solution by placing trays holding the lenses. Before rinsing the lenses, the trays may need to be transferred to a second container having a rinsing solution. Significant manual handling of the lens may be required in transferring lenses from one treatment to another. Such operation may not be efficient or cost-effective.
Furthermore, there are problems associated with the lenses resting against the tray compartments or associated with gas bubbles being attached to the lenses. For example, an extended contact period of the lens with the tray causes concentration gradients, resulting in lenses which are non-uniformly tinted or non-uniformly surface-modified. Attached bubbles prevent a treatment solution from contacting all parts of a lens and thereby prevent the lens from being treated uniformly during a washing, extracting, coating, or tinting process.
Thus, there is a need for a method of treating contact lenses with one or more solution in an efficient, economical, uniform manner. There also remains a need for a wet treatment system for contact lenses in which all of wet treatment processes such as extraction, rinsing, hydration, tinting, and coating can be carried without transferring lenses.
An object of the invention is to provide a single system for efficiently and uniformly treating articles with one or more fluids.
Another object of the invention is to provide a method of efficiently and uniformly treating articles with a fluids.
A further object of the invention is to provide a method of sequentially treating articles with two or more fluids without needs for transferring lenses from one container to another container.